1. Field
Exemplary embodiments of the present invention relate to an integrated circuit chip and a mobile device including the same, and more particularly, to a technology for efficiently using an impedance matching function.
2. Description of the Related Art
Various integrated circuit chips such as CPUs, memories, or gate arrays are embedded in various electrical products such as personal computers, servers, or mobile phones. In most cases, the integrated circuit chip has a receiver for receiving various signals, which are transmitted from an outside, through an input pad, and a transmitter for transmitting internal signals externally through an output pad.
Meanwhile, as an electrical product operates at a high speed, an impedance matching between integrated circuit chips becomes very important. When an impedance mismatching occurs, signals transferred at a high speed between the chips may be reflected, and thus a certain receiver may not normally recognize the signals.
FIG. 1 is a diagram illustrating an impedance matching circuit used in a conventional integrated circuit chip.
Referring to FIG. 1, the integrated circuit chip includes a pull-up resistor 101 and a pull-down resistor 102, a pull-up switch SW1 and a pull-down switch SW2. The integrated circuit chip performs an impedance matching operation of an input/output pad I/O PAD by terminating the input/output pad I/O PAD in pull-up and pull-down directions. An on/off signal ON/OFF, applied to the pull-up and pull-down switches SW1 and SW2, is for turning on/off the impedance matching circuit.
When the impedance matching circuit is turned on, impedance of a transmission channel connected to the input/output pad I/O PAD is matched, so that a signal can be stably input and output. When the impedance matching circuit is turned on, a current path is formed from a power supply voltage terminal VDD to a ground terminal VSS through the pull-up resistor 101 and the pull-down resistor 102. Although the use of the impedance matching circuit guarantees stable signal transmission, simultaneously causes high current consumption. Due to the high current consumption in the impedance matching circuit, an integrated circuit chip in most devices driven by a battery does not use the impedance matching circuit. For example, although the impedance matching circuit is provided in a memory chip used in a mobile device, the impedance matching circuit is generally deactivated.